EP0319323A2 - Infinitely variable steering transmission - Google Patents
Infinitely variable steering transmission Download PDFInfo
- Publication number
- EP0319323A2 EP0319323A2 EP88311457A EP88311457A EP0319323A2 EP 0319323 A2 EP0319323 A2 EP 0319323A2 EP 88311457 A EP88311457 A EP 88311457A EP 88311457 A EP88311457 A EP 88311457A EP 0319323 A2 EP0319323 A2 EP 0319323A2
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- EP
- European Patent Office
- Prior art keywords
- output
- transmission
- gear set
- speed
- planetary gear
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D3/00—Steering gears
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
- B62D11/02—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides
- B62D11/06—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source
- B62D11/10—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source using gearings with differential power outputs on opposite sides, e.g. twin-differential or epicyclic gears
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19023—Plural power paths to and/or from gearing
- Y10T74/19037—One path includes fluid drive
Definitions
- the present invention relates to infinitely variable steering transmission.
- the present invention relates, for example, to multi-range steering transmissions for track-laying or skid-steered, wheeled vehicles.
- An exemplary steering transmission of this type typically utilizes at least one and in most instances two separate hydraulic drive units mechanically driven by a prime mover at a normally constant speed and capable of developing within limits, infinitely variable speed, bidirectional, hydrostatic outputs for ultimate application to the left and right transmission output shafts.
- These hydrostatic outputs are typically utilized alone to hydrostatically drive the transmission output shafts in a forward and reverse first propulsion range and are combined with mechanical inputs from the prime mover to hydromechanically drive the transmission output shafts in at least one and typically several higher forward propulsion ranges.
- Changes in the hydrostatic output speed provide infinite speed variation within the various ranges and ideally can also be utilized to effect steering by differentially varying the speeds of the two hydrostatic outputs.
- a typical hydraulic drive unit may be of the type disclosed in Applicant's U.S. Patent No. 3,815,698 entitled "Hydromechanical Steering Transmission” and, as such, includes a variable capacity ball piston pump and a normally fixed capacity ball piston motor connected in hydraulic fluid-coupled relation.
- the pumps are driven at a constant speed by the prime mover, and the motors develop the hydrostatic outputs.
- the pump capacities i.e., "stroking” as it is known in the art
- the speeds of the motor hydrostatic outputs are varied accordingly.
- the eccentricity of the pumps the rotational direction of the motor hydrostatic outputs are reversed.
- One aspect of the present invention seeks to provide an infinitely variable steering transmission for e.g. a track-laying vehicle.
- An additional aspect seeks to provide an infinitely variable steering transmission wherein the infinitely variable speed capability is provided in a simplified and efficient manner.
- a further aspect seeks to provide an infintely variable steering transmission which is inexpensive to manufacture, requires a relatively low number of component parts, and is compact and light in weight, and is efficient in operation.
- an infinitely variable steering transmission e.g. for track-laying vehicles, which utilizes drive units of the type which are capable of developing, in response to a constant speed mechanical input, an output speed infinitely variable between a minimum speed less than input speed and a maximum speed greater than input speed.
- drive units can not however provide neutral (zero output speed) and their outputs are unidirectional (non-reversing).
- variable speed outputs of the two drive units are respectively applied to left and right output planetary gear sets drivingly connected with the left and right transmission output shafts.
- the constant speed mechanical input of the prime mover is applied via an input planetary gear set to both output planetary gear sets for interaction with the drive unit outputs to drive the transmission output shafts through either a forward and reverse first propulsion range or a forward third propulsion range depending upon the reaction to the prime mover constant speed mechanical input selectively established in the input planetary gear set.
- This constant speed mechanical input also fixes the speeds of corresponding gear elements of both output planetary gear sets during first and third range steering maneuvers effected by increasing the output speed of one drive unit by the same increment that the output speed of the other drive unit is decreased.
- the input planetary gear set is inactivated, and thus the transmission output shafts are driven exclusively by the drive unit outputs.
- the outputs of both drive units are combined by one of the output planetary gear sets to produce a steer cancelling effect in both output planetary gear sets, to establish the same steering convention as exists in the first and third ranges, and to accommodate a speed stroking control pattern for the drive units which is devoid of discontinuities as the vehicle is accelerated through the forward propulsion ranges.
- the track laying vehicle steering transmission generally indicated at 10 in FIGURE 1 includes a first drive unit 12 and a second, identical drive unit 14.
- These drive units are a type of transmission unit that provides in response to a constant speed input drive, an infinitely variable speed output ranging from some minimum speed less than input speed to some maximum speed greater than input speed.
- Other characteristics of this type of drive unit are that its direction of output drive cannot be reversed, i.e., no reverse capability, and its output speed does not go to zero, i.e., no neutral.
- Such drive units may take a variety of forms, such as toroidal traction drive units, V-belt drives having variable diameter pulleys, and the like.
- the identical, input drives to drive units 12 and 14, indicated at 13 and 15, respectively, are obtained from a suitable vehicle prime mover 8, such as a diesel or gas turbine engine operating at constant speed.
- the variable speed output of drive unit 12 appears on output shaft 16 on which is mounted a pinion gear 18 which drives a spur gear 22 carried by a sleeve shaft 24.
- the sun gear 26s of a right output planetary gear set are also carried by this sleeve shaft.
- the same constant speed input drive that is applied to drive units 12 and 14 is also applied, as indicated at 27, to a spur gear 28 mounted on a sleeve shaft 30 which also carries the sun gear 32s of an input planetary gear set, generally indicated at 32.
- Planetary pinion gears 32p of input planetary gear set 32 and planetary pinion gears 26p of output planetary gear set 26 are mounted on a common carrier, indicated at 34. Ring gear 26r of the output planetary gear set is directly connected to the right transmission output shaft 36. Ring gear 32r of input planetary gear set 32 is grounded upon activation of a brake BI(R) to put transmission 10 in a forward/reverse first speed range.
- Output shaft 40 of drive unit 14 carries a pinion gear 42 which meshes with a spur gear 44 carried on a sleeve shaft 46.
- the ratio between gears 42 and 44 is the same as the ratio between gears 18 and 22.
- Sleeve shaft 46 also mounts the sun gear 48s of a left output planetary gear set, generally indicated at 48.
- Pinion gears 48p are mounted on a planetary carrier 48c which is physically connected via a cross shaft 50 to the common carrier 34 of planetary gear sets 32 and 26.
- Ring gear 48r of the left output planetary gear set 48 is directly connected with the left transmission output shaft 52.
- Brakes B1 and B2 are activated to ground ring gears 48r and 26r, respectively, and thus serve as vehicles stopping and parking brakes.
- output shaft 16 of drive unit 12 Upon engagement of a clutch CII, output shaft 16 of drive unit 12 also drives a pinion gear 54 which, in turn, drives a spur gear 58 directly connected to ring gear 48r of left output planetary gear set 48.
- clutch CII is engaged to apply the variable speed output of drive unit 12 to ring gear 48r of left output planetary gear set 48 and thence to left transmission output shaft 52 when transmission 10 is shifted into a second forward propulsion speed range.
- brake BI(R) is engaged to ground ring gear 32r of input planetary gear set 32. Since the constant speed prime mover input is driving sun gear 32s of input planetary gear set 32, common carrier 34 is driven at a reduced constant speed determined by the sun to carrier reduction of this planetary gear set. By virtue of the interconnecting cross shaft 50, planetary carrier 48c of left output planetary gear set 48 is driven at the same fixed reduced speed as common planetary carrier 34.
- variable speed output of drive unit 12 is being applied as a separate mechanical input to sun gear 26s
- variable speed output drive of drive unit 14 is being applied as yet another separate mechanical input to sun gear 48s.
- the two output ring gears 26r and 48r and thus transmission output shafts 36 and 52 are driven into rotation at speeds which are functions of the two mechanical inputs applied to each of the two output planetary gear sets.
- FIGURE 2 is a graphical illustration of the relative angular velocities of the various elements of the two output planetary gear sets.
- vertical line 60 represents the velocity operating range of sun gear 48s
- vertical line 61 represents the velocity operating range of carrier 48c
- vertical line 62 represents the velocity operating range of ring gear 48r.
- vertical lines 63, 64 and 65 represent the velocity operating range of sun gear 26s, carrier 34, and ring gear 26r, respectively.
- the horizontal separation of vertical lines 60 and 61 is proportional to the number of teeth on ring gear 48r, while the horizontal separation of vertical lines 61 and 62 is proportional to the number of teeth on sun gear 48s.
- the horizontal separation between vertical lines 60 and 62 is proportional to the sum of the ring gear 48r and sun gear 48s teeth.
- the same proportionalities apply for the horizontal separations between vertical lines 63 - 65 for output planetary gear set 26. Since the two output planetary gear sets are of identical gears ratios, the separations between corresponding vertical lines are identical in each case.
- X axis 66 represents zero revolutions per minute (RPM), and points on vertical operating lines 60 - 65 correspond to the angular velocities of the respective planetary gear elements represented by these lines.
- Points above this axis 66 represent angular velocities in the forward propulsion direction, while points below this axis represent angular velocities in the reverse propulsion direction.
- a characteristic of planetary gears such as planetary gear 26 and 48 is that, under all operating conditions, the velocity points on the vertical operating lines of the various planetary gear elements will always lie on a single straight line. Thus, when two of the velocity operating points of the three planetary gear elements are known, the third velocity point will always lie on a straight line drawn through the two known velocity points.
- drive units 12 and 14 are capable of producing output speeds varying from a predetermined reduction relative to constant input speeds to a predetermined overdrive relative to constant input speed. It will be assumed that these drive units are capable of providing infinitely variable output speeds ranging from a two to one reduction relative to input speed to a one to two step up or overdrive relative to input speed.
- velocity points 67, 68 and 69 on sun gear 48s vertical operating line 60 represent drive unit speed ratios of two to one, one to one and one to two, respectively.
- Velocity point 70 represents the mid point speed of this velocity spectrum, which is 1 to 1.25.
- Corresponding velocity points 67 - 70 are also shown on sun gear 26s vertical operating line 63.
- the gear ratio of input planetary gear set 32 and the identical gear ratios for the two output planetary gear sets 26, 48 are established such that when sun gear 26s is driven by drive unit 12 at an angular velocity which corresponds to the midpoint of its velocity spectrum, i.e., velocity point 70 on line 63, the angular velocity of ring gear 26r is zero.
- This operating condition is satisfied if common carrier 34 is made to rotate by the prime mover acting through planetary gear set 32 at a velocity corresponding to point 71. Under these conditions, a straight line 72 drawn through points 70 and 71 intersects ring gear 26r operating line 65 at point 72 which lies on zero velocity axis 66.
- the preferred convention for executing a steer is to increase the output speed of one drive unit 12, 14 by a predetermined amount, while decreasing the output speed of the other drive unit by the same predetermined amount. This has the effect of proportionately increasing the output speed of one transmission output shaft 36, 52 while decreasing the output speed of the other transmission output shaft by an equal amount. It can readily be seen from FIGURE 2 that if the angular velocity of sun gear 26s is increased a given amount by increasing the output speed of drive unit 12, and the angular velocity of sun gear 48s is decreased by the same amount by decreasing the output speed of drive unit 14, the angular velocities of ring gears 26r and 48r respectively decrease and increase by equal amounts to effect a steer to the right.
- a steer to the left is executed.
- the execution of a steer simply results in the straight operating line for planetary gear set 26 being rocked about the fixed velocity point of its carrier 34 in one direction, while the straight operating line for planetary gear set 48 is rocked through an equal arc in the opposite direction about the fixed velocity point of its carrier 48c; these carrier velocity points thus serving as fulcrums.
- the degree of steer may be varied by increasing or decreasing the magnitudes of the increments by which the output speeds of the drive units are increased on the one hand and decreased on the other.
- third forward propulsion range operation Before describing the operation of transmission 10 in its second forward propulsion range, third forward propulsion range operation will be described because it is basically identical to first forward propulsion range operation.
- brake BI(R) is released.
- third range clutch CIII is engaged. This is seen to apply the constant speed input of prime mover 8 on sleeve shaft 30 directly to common planetary carrier 34 and also to planetary carrier 48c via cross shaft 50. In FIGURE 2 this is seen to impose an angular velocity on these carriers which is represented by velocity points 80 on carrier vertical operating lines 61 and 64 which are horizontally aligned with points 68 on sun gear 48s vertical operating line 60 and sun gear 26s vertical operating line 63.
- velocity points 68 correspond to a one to one speed ratio being established in drive units 12 and 14, and thus their output speeds are both equal to the speed of the prime mover mechanical input. It is seen that speed variations in the third propulsion range are effected in exactly the same manner as in the first propulsion range.
- Drive units 12 and 14 are uniformly stroked downwardly in speed from points 69 on the sun gear vertical operating lines to velocity points 67 in order to speed up through the third propulsion range. This is confirmed in FIGURE 2 as straight lines 81 drawn for the two output planetary sets from points 69 through points 80 intersect the ring gear vertical operating lines at points 82, which represent minimum speed in the third propulsion range.
- third forward propulsion speed range can be represented by the double pointed arrows 85 in Figure 2.
- Third range steer is effected simply by respectively increasing and decreasing the output speeds of drive limits 12 and 14 by equal amounts, which has the effect of rocking operating lines of the left and right output planetry gear sets through equal angles in opposite directions about the fixed velocity point flucrums 80 imposed on carriers 48c and 34 by the constant speed prime mover input.
- brake BI(R) is released, and second range clutch CII is engaged.
- FIGURE 1 This is seen in FIGURE 1 to create the condition wherein the variable speed output of drive unit 12 is applied not only to sun gear 26s of right output planetary gear set 26, but also to ring gear 48r of left output planetary gear set 48 via pinion gear 54 and spur gear 58.
- left output planetary gear set 48 receives two mechanical inputs, the first being the variable speed output of drive unit 14 on its sun gear 48s and the second being the variable speed output of drive unit 12 on its ring gear 48r.
- brake BI(R) since brake BI(R) is released, there is no reaction force in input planetary gear set 32 to the prime mover input on sun gear 32s, and thus this constant speed input does not drive common carrier 34 during second range forward propulsion.
- the straight operating line 88 for right output planetary gear 26 drawn through points 70 and 89 intersects the ring gear 26r vertical operating line 65 at point 87 whose vertical position is the same as that of velocity point 87 on ring gear 48r vertical operating line 62. From the foregoing description, it can be seen that the second forward propulsion range fills in the gap between the first and third forward propulsion ranges, with second range limits represented by double pointed arrows 95.
- the drive units are stroked downwardly, as represented by straight line section 90a through first range propulsion in the reverse and then forward directions, stroked upwardly, as represented by straight line segment 90b, for forward propulsion through the second range, and then stroked downwardly, as represented by straight line segment 90c, for forward propulsion in the third range.
- This drive unit stroking pattern is continuous from range to range, and thus range shifting does not require abrupt changes in drive unit speed.
- second range steer It is obviously extremely important that the steering convention as described above with respect to the first and third ranges be the same for the second range. That is, operator control and vehicle response during its steer should not vary from range to range.
- steering in all three range must be effected by the same equal and opposite strokings of the two drive units 12 and 14. That is, a steer to the right must be effected by increasing the output speed of drive unit 12 by a preselected amount accompanied by decreasing the output speed of drive unit 14 by the same amount, and vice versa.
- the mechanical speed inputs to the left output planetary gear set must be such that as the angular velocities of ring gear 48r and sun gear 48s are varied in relatively opposite directions, an average of these two speed inputs must be developed on carrier 48c. That is, an increase in the angular velocity of sun gear 48s which would tend to increase the angular velocity of carrier 48c must be exactly offset by an appropriate decrease in the angular velocity of ring gear 48r.
- second range clutch CII becomes synchronous, i.e., output shaft 16 of drive unit 12 is rotating at the same angular velocity as pinion 54 is being rotated by ring gear 48r via spur gear 58. This represents an opportune time to shift from the first forward propulsion range into the second forward propulsion range by engaging clutch CII and releasing brake BI(R).
- third range clutch CIII becomes synchronous in that carrier 34 is revolving at the same angular velocity as sleeve shaft 30. At this time, shifting from the second forward propulsion range into the third propulsion range can be smoothly effected by engaging the third range clutch CIII as clutch CII is disengaged.
- first second and third range forward propulsion limits represented in FIGURE 3 by arrows 78, 95 and 85, respectively, are not in practice end-to-end as illustrated.
- At least twenty percent of the first range extends at its upper end into the lower end of the second speed range, and at least twenty percent of the second speed range extends at its upper end into the lower end of the third speed range to accommodate the synchronous range shifting described above.
- This speed overlap is also desirable to have available additional speed variation in the drive units 12, 14 for steering while the transmission is being operated near its range shifting points.
- an illustrative multi-range, infinitely variable, integral steering transmission for track-laying vehicles which is compact in size and inexpensive to manufacture, requires a minimal number of component parts, is efficient in operation and affords positive and uniform operator control in all of its multiple speed ranges.
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- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
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Abstract
Description
- The present invention relates to infinitely variable steering transmission.
- The present invention relates, for example, to multi-range steering transmissions for track-laying or skid-steered, wheeled vehicles.
- An exemplary steering transmission of this type typically utilizes at least one and in most instances two separate hydraulic drive units mechanically driven by a prime mover at a normally constant speed and capable of developing within limits, infinitely variable speed, bidirectional, hydrostatic outputs for ultimate application to the left and right transmission output shafts. These hydrostatic outputs are typically utilized alone to hydrostatically drive the transmission output shafts in a forward and reverse first propulsion range and are combined with mechanical inputs from the prime mover to hydromechanically drive the transmission output shafts in at least one and typically several higher forward propulsion ranges. Changes in the hydrostatic output speed provide infinite speed variation within the various ranges and ideally can also be utilized to effect steering by differentially varying the speeds of the two hydrostatic outputs.
- A typical hydraulic drive unit may be of the type disclosed in Applicant's U.S. Patent No. 3,815,698 entitled "Hydromechanical Steering Transmission" and, as such, includes a variable capacity ball piston pump and a normally fixed capacity ball piston motor connected in hydraulic fluid-coupled relation. The pumps are driven at a constant speed by the prime mover, and the motors develop the hydrostatic outputs. By varying the pump capacities, i.e., "stroking" as it is known in the art, the speeds of the motor hydrostatic outputs are varied accordingly. Also, by reversing the eccentricity of the pumps, the rotational direction of the motor hydrostatic outputs are reversed.
- One aspect of the present invention seeks to provide an infinitely variable steering transmission for e.g. a track-laying vehicle.
- An additional aspect seeks to provide an infinitely variable steering transmission wherein the infinitely variable speed capability is provided in a simplified and efficient manner.
- A further aspect seeks to provide an infintely variable steering transmission which is inexpensive to manufacture, requires a relatively low number of component parts, and is compact and light in weight, and is efficient in operation.
- In accordance with an embodiment of the present invention, there is provided an infinitely variable steering transmission, e.g. for track-laying vehicles, which utilizes drive units of the type which are capable of developing, in response to a constant speed mechanical input, an output speed infinitely variable between a minimum speed less than input speed and a maximum speed greater than input speed. These drive units can not however provide neutral (zero output speed) and their outputs are unidirectional (non-reversing).
- The variable speed outputs of the two drive units are respectively applied to left and right output planetary gear sets drivingly connected with the left and right transmission output shafts. The constant speed mechanical input of the prime mover is applied via an input planetary gear set to both output planetary gear sets for interaction with the drive unit outputs to drive the transmission output shafts through either a forward and reverse first propulsion range or a forward third propulsion range depending upon the reaction to the prime mover constant speed mechanical input selectively established in the input planetary gear set. This constant speed mechanical input also fixes the speeds of corresponding gear elements of both output planetary gear sets during first and third range steering maneuvers effected by increasing the output speed of one drive unit by the same increment that the output speed of the other drive unit is decreased. To operate the transmission in a forward second propulsion range, the input planetary gear set is inactivated, and thus the transmission output shafts are driven exclusively by the drive unit outputs. In addition, the outputs of both drive units are combined by one of the output planetary gear sets to produce a steer cancelling effect in both output planetary gear sets, to establish the same steering convention as exists in the first and third ranges, and to accommodate a speed stroking control pattern for the drive units which is devoid of discontinuities as the vehicle is accelerated through the forward propulsion ranges. By appropriate selection of gear ratios, shifting from range to range is made synchronous.
- For a better understanding of the invention, reference may be had to the following illustrative description taken in conjunction with the accompanying drawings, in which
- FIGURE 1 is a schematic illustration of an illustrative infinitely variable steering transmission constructed in accordance with the present invention;
- FIGURE 2 is a graph illustrating the operations of the two output planetary gear sets in the steering transmission of FIGURE 1; and
- FIGURE 3 is a graph of drive unit speed (RPM) versus vehicle speed (MPH) to illustrate the stroking pattern for the drive units in the transmission of FIGURE 1 to achieve acceleration through the plural speed ranges.
- Corresponding reference numerals refer to like parts throughout the various figures of the drawings.
- The track laying vehicle steering transmission generally indicated at 10 in FIGURE 1, includes a
first drive unit 12 and a second,identical drive unit 14. These drive units are a type of transmission unit that provides in response to a constant speed input drive, an infinitely variable speed output ranging from some minimum speed less than input speed to some maximum speed greater than input speed. Other characteristics of this type of drive unit are that its direction of output drive cannot be reversed, i.e., no reverse capability, and its output speed does not go to zero, i.e., no neutral. Such drive units may take a variety of forms, such as toroidal traction drive units, V-belt drives having variable diameter pulleys, and the like. The identical, input drives to driveunits vehicle prime mover 8, such as a diesel or gas turbine engine operating at constant speed. The variable speed output ofdrive unit 12 appears onoutput shaft 16 on which is mounted apinion gear 18 which drives aspur gear 22 carried by asleeve shaft 24. Also carried by this sleeve shaft is thesun gear 26s of a right output planetary gear set, generally indicated at 26. The same constant speed input drive that is applied to driveunits spur gear 28 mounted on asleeve shaft 30 which also carries the sun gear 32s of an input planetary gear set, generally indicated at 32.Planetary pinion gears 32p of input planetary gear set 32 andplanetary pinion gears 26p of outputplanetary gear set 26 are mounted on a common carrier, indicated at 34.Ring gear 26r of the output planetary gear set is directly connected to the righttransmission output shaft 36. Ring gear 32r of inputplanetary gear set 32 is grounded upon activation of a brake BI(R) to puttransmission 10 in a forward/reverse first speed range. -
Output shaft 40 ofdrive unit 14 carries apinion gear 42 which meshes with aspur gear 44 carried on asleeve shaft 46. The ratio betweengears gears Sleeve shaft 46 also mounts thesun gear 48s of a left output planetary gear set, generally indicated at 48.Pinion gears 48p are mounted on aplanetary carrier 48c which is physically connected via across shaft 50 to thecommon carrier 34 ofplanetary gear sets Ring gear 48r of the left outputplanetary gear set 48 is directly connected with the lefttransmission output shaft 52. Brakes B1 and B2 are activated toground ring gears - Upon engagement of a clutch CII,
output shaft 16 ofdrive unit 12 also drives apinion gear 54 which, in turn, drives aspur gear 58 directly connected toring gear 48r of left outputplanetary gear set 48. As will be seen, clutch CII is engaged to apply the variable speed output ofdrive unit 12 toring gear 48r of left outputplanetary gear set 48 and thence to lefttransmission output shaft 52 whentransmission 10 is shifted into a second forward propulsion speed range. - Completing the structure of
transmission 10 seen in FIGURE 1, the constant input speed drive from theprime mover 8, indicated at 27 and appearing onsleeve shaft 30, is applied upon engagement of clutch CIII to directly drive thecommon carrier 34 ofplanetary gear sets carrier 48c of planetary gear set 48 viacross shaft 50. Thus the engagement of clutch CIII shiftstransmission 8 into a third forward propulsion speed range. - As noted above, to shift
transmission 10 into the forward/reverse first speed range, brake BI(R) is engaged to ground ring gear 32r of inputplanetary gear set 32. Since the constant speed prime mover input is driving sun gear 32s of inputplanetary gear set 32,common carrier 34 is driven at a reduced constant speed determined by the sun to carrier reduction of this planetary gear set. By virtue of the interconnectingcross shaft 50,planetary carrier 48c of left outputplanetary gear set 48 is driven at the same fixed reduced speed as commonplanetary carrier 34. While these two output planetary gear carriers are being revolved in unison by the mechanical input obtained fromprime mover 8, the variable speed output ofdrive unit 12 is being applied as a separate mechanical input tosun gear 26s, and the variable speed output drive ofdrive unit 14 is being applied as yet another separate mechanical input tosun gear 48s. As a consequence, the twooutput ring gears transmission output shafts - To more readily appreciate the operation of the output
planetary gear sets planetary gear set 48,vertical line 60 represents the velocity operating range ofsun gear 48s,vertical line 61 represents the velocity operating range ofcarrier 48c andvertical line 62 represents the velocity operating range ofring gear 48r. Similarly with regard to right output planetary gear set 26,vertical lines sun gear 26s,carrier 34, andring gear 26r, respectively. The horizontal separation ofvertical lines ring gear 48r, while the horizontal separation ofvertical lines sun gear 48s. Thus, the horizontal separation betweenvertical lines ring gear 48r andsun gear 48s teeth. The same proportionalities apply for the horizontal separations between vertical lines 63 - 65 for outputplanetary gear set 26. Since the two output planetary gear sets are of identical gears ratios, the separations between corresponding vertical lines are identical in each case.X axis 66 represents zero revolutions per minute (RPM), and points on vertical operating lines 60 - 65 correspond to the angular velocities of the respective planetary gear elements represented by these lines. Points above thisaxis 66 represent angular velocities in the forward propulsion direction, while points below this axis represent angular velocities in the reverse propulsion direction. A characteristic of planetary gears such asplanetary gear - As was noted above,
drive units velocity points sun gear 48svertical operating line 60 represent drive unit speed ratios of two to one, one to one and one to two, respectively.Velocity point 70 represents the mid point speed of this velocity spectrum, which is 1 to 1.25. Corresponding velocity points 67 - 70 are also shown onsun gear 26svertical operating line 63. Preferably, the gear ratio of input planetary gear set 32 and the identical gear ratios for the two output planetary gear sets 26, 48 are established such that whensun gear 26s is driven bydrive unit 12 at an angular velocity which corresponds to the midpoint of its velocity spectrum, i.e.,velocity point 70 online 63, the angular velocity ofring gear 26r is zero. This operating condition is satisfied ifcommon carrier 34 is made to rotate by the prime mover acting through planetary gear set 32 at a velocity corresponding to point 71. Under these conditions, astraight line 72 drawn throughpoints ring gear 26r operatingline 65 atpoint 72 which lies on zerovelocity axis 66. Sinceplanetary carrier 34 is rigidly connected toplanetary carrier 48c by cross shaft 50 (FIGURE 1), the latter carrier must therefore be driven at the same speed which is also represented byvelocity point 71 onvertical operating line 61. Thus, astraight line 72 drawn throughoperating point 71 oncarrier 48cvertical operating line 61 andoperating point 70 onsun gear 48svertical operating line 60 intersectsring gear 48rvertical operating line 62 at point 73 which also lies on the zerovelocity axis 66. - If
drive units sun gear 26svertical operating line 63 andsun gear 48svertical operating line 60 toward their upper speed limits atpoints 69, ring gears 26r and 48r, and with themtransmission output shafts interconnected carriers straight lines 75. If the output speeds ofdrive units straight lines 76 drawn through velocity points 67 and 71 for both output planetary gear sets are seen to intersectring gear 26rverticle operating line 65 andring gear 48rverticle operating line 62 atcorresponding points 77 which represent maximum first range forward speed. Thus, the first forward propulsion speed range is represented by the double pointedarrows 78, while the first reverse propulsion speed range is represented by the double pointedarrows 79. - The preferred convention for executing a steer, and the one utilized in the present embodiment, is to increase the output speed of one
drive unit transmission output shaft sun gear 26s is increased a given amount by increasing the output speed ofdrive unit 12, and the angular velocity ofsun gear 48s is decreased by the same amount by decreasing the output speed ofdrive unit 14, the angular velocities of ring gears 26r and 48r respectively decrease and increase by equal amounts to effect a steer to the right. By the same token, decreasing the output speed ofdrive unit 12 by the same amount that the output speed ofdrive unit 14 is increased, a steer to the left is executed. Thus, the execution of a steer simply results in the straight operating line for planetary gear set 26 being rocked about the fixed velocity point of itscarrier 34 in one direction, while the straight operating line for planetary gear set 48 is rocked through an equal arc in the opposite direction about the fixed velocity point of itscarrier 48c; these carrier velocity points thus serving as fulcrums. Obviously, the degree of steer may be varied by increasing or decreasing the magnitudes of the increments by which the output speeds of the drive units are increased on the one hand and decreased on the other. - Before describing the operation of
transmission 10 in its second forward propulsion range, third forward propulsion range operation will be described because it is basically identical to first forward propulsion range operation. - To shift
transmission 10 out of its first range, brake BI(R) is released. To shift from the second forward propulsion range to the third forward propulsion range, third range clutch CIII is engaged. This is seen to apply the constant speed input ofprime mover 8 onsleeve shaft 30 directly to commonplanetary carrier 34 and also toplanetary carrier 48c viacross shaft 50. In FIGURE 2 this is seen to impose an angular velocity on these carriers which is represented by velocity points 80 on carriervertical operating lines points 68 onsun gear 48svertical operating line 60 andsun gear 26svertical operating line 63. This is so since, as noted above, velocity points 68 correspond to a one to one speed ratio being established indrive units units points 69 on the sun gear vertical operating lines to velocity points 67 in order to speed up through the third propulsion range. This is confirmed in FIGURE 2 asstraight lines 81 drawn for the two output planetary sets frompoints 69 throughpoints 80 intersect the ring gear vertical operating lines atpoints 82, which represent minimum speed in the third propulsion range. Also,straight lines 83 drawn throughpoints arrows 85 in Figure 2. Third range steer is effected simply by respectively increasing and decreasing the output speeds of drive limits 12 and 14 by equal amounts, which has the effect of rocking operating lines of the left and right output planetry gear sets through equal angles in opposite directions about the fixedvelocity point flucrums 80 imposed oncarriers - As mentioned above, to shift
transmission 10 from its first forward propulsion range to its second forward propulsion range, brake BI(R) is released, and second range clutch CII is engaged. This is seen in FIGURE 1 to create the condition wherein the variable speed output ofdrive unit 12 is applied not only to sungear 26s of right output planetary gear set 26, but also toring gear 48r of left output planetary gear set 48 viapinion gear 54 andspur gear 58. Thus, left output planetary gear set 48 receives two mechanical inputs, the first being the variable speed output ofdrive unit 14 on itssun gear 48s and the second being the variable speed output ofdrive unit 12 on itsring gear 48r. Also, since brake BI(R) is released, there is no reaction force in input planetary gear set 32 to the prime mover input on sun gear 32s, and thus this constant speed input does not drivecommon carrier 34 during second range forward propulsion. - From FIGURE 2 it is seen that, in first range, as
drive units points 67, ring gears 48r and 26r uniformly increase in velocity toward maximum first range forward speed corresponding to points 77. When second range clutch CII is engaged,drive unit 12 then begins drivingring gear 48r at a velocity proportional to the ratio established betweenpinion gear 54 andspur gear 58. It is now seen that, with regard to left output planetary gear set 48, uniformly stroking thedrive units sun gear 48sverticle operating line 60 to move upwardly as does thevelocity point 77 onring gear 48rverticle operating line 62. Thus, as thedrive units sun gear 48svertical operating line 60 andring gear 48rvertical operating line 62 uniformly move up (acceleration) and down (deceleration) at fixed proportionate rates determined by the ratio betweenpinion gear 54 andring gear 58. Under these circumstances,carrier 48c velocity point must move upwardly and downwardly on itsvertical operating line 61 correspondingly in order to satisfy the straight line operating rule for planetary gear sets. For example, ifdrive unit 14 is stroked upwardly during second range operation fromvelocity point 67 onsun gear 48svertical operating line 60 to mid-range speed corresponding tovelocity point 70,ring gear 48r will have been driven upwardly bydrive unit 12 fromvelocity point 77 tovelocity point 87 which corresponds to the mid-speed point in the second forward propulsion range. Whenstraight line 88 is drawn betweenpoints velocity point 71 oncarrier 48cvertical operating line 61 must move upwardly to point 89. - Now looking at the right hand output planetary gear set 26, since the
carrier 48c of the left output planetary gear set 48 is connected tocarrier 34 of the right output planetary gear set bycross shaft 50, these carriers must revolve at the same speed. Thus during mid-speed second range operation,velocity point 89 oncarrier 34vertical operating line 64 must assume relatively the same vertical position on the graph as does thevelocity point 89 on thecarrier 48c vertical operating line. Since straight ahead propulsion calls for the output speeds ofdrive units sun gear 26s is driven at a velocity corresponding to point 70 onvertical operating line 63. Thus, thestraight operating line 88 for right outputplanetary gear 26 drawn throughpoints ring gear 26rvertical operating line 65 atpoint 87 whose vertical position is the same as that ofvelocity point 87 onring gear 48rvertical operating line 62. From the foregoing description, it can be seen that the second forward propulsion range fills in the gap between the first and third forward propulsion ranges, with second range limits represented by doublepointed arrows 95. This graphical demonstration that the speed imposed onring gear 48r and thus leftoutput shaft 52 bydrive unit 12 is duplicated onright output shaft 36, can also be readily seen in FIGURE 1 since, during straight ahead second range propulsion, the sun gears and carriers of the two identical planetary gear sets are respectively moving at the same angular velocities, and therefore their ring gears are constrained to move at the same angular velocity as well. - From the foregoing description and as graphically illustrated in Figure 3, wherein the Y axis represents the common output speed in RPM of
drive units straight line section 90a through first range propulsion in the reverse and then forward directions, stroked upwardly, as represented bystraight line segment 90b, for forward propulsion through the second range, and then stroked downwardly, as represented bystraight line segment 90c, for forward propulsion in the third range. This drive unit stroking pattern is continuous from range to range, and thus range shifting does not require abrupt changes in drive unit speed. - Still to be considered is second range steer. It is obviously extremely important that the steering convention as described above with respect to the first and third ranges be the same for the second range. That is, operator control and vehicle response during its steer should not vary from range to range. Thus, if the steer power path in the transmission is to avoid the utilization of added gear elements and clutches, steering in all three range must be effected by the same equal and opposite strokings of the two
drive units drive unit 12 by a preselected amount accompanied by decreasing the output speed ofdrive unit 14 by the same amount, and vice versa. With reference to FIGURE 2, it is seen that this can be achieved intransmission 10 if the positions of the velocity points forcarriers drive units drive unit 14 is stroked downwardly to lower the position of the velocity point onsun gear 48svertical operating line 60 and the position of the velocity point oncarrier 48c's vertical operating line remains unchanged, the left output planetary gear operating line simply rocks in the counterclockwise direction about the fixed position of thecarrier 48c velocity point, and thus the velocity point onring gear 48r vertical operating line must move up by a proportionate amount. By the same token, whendrive unit 12 is stroked upwardly by the same amount asdrive unit 14 is stroked downwardly, the straight operating line for right outputplanetary gear 26 is rocked in the opposite or counterclockwise direction about the fixed position ofcarrier 34 velocity point, and thus the velocity point forring gear 26r must move downwardly by a corresponding amount. It is thus seen under these circumstances that the speed ofring gear 48r is increased by the same amount that the speed ofring gear 26r is decreased, and the vehicle is steered to the right. A steer to the left is seen in FIGURE 2 to be effected by strokingdrive unit 14 upwardly in speed by the same amount that driveunit 12 is stroked downwardly in speed. It will be recognized that this is exactly the same steering convention that applied in the first and third ranges. - To ensure that the angular velocity of
carrier 48c is unaffected during a second range steer, the mechanical speed inputs to the left output planetary gear set must be such that as the angular velocities ofring gear 48r andsun gear 48s are varied in relatively opposite directions, an average of these two speed inputs must be developed oncarrier 48c. That is, an increase in the angular velocity ofsun gear 48s which would tend to increase the angular velocity ofcarrier 48c must be exactly offset by an appropriate decrease in the angular velocity ofring gear 48r. It has been determined that this offsetting or steer canceling effect is obtained if the ratio ofspur gear 44 topinion gear 42 multiplied by the ratio ofpinion gear 54 to spurgear 58 is equal to the ratio ofsun gear 48s to ringgear 48r. Also by virtue of this particular gearing relationship, it is found that at 80 percent of maximum speed in the first forward propulsion range, second range clutch CII becomes synchronous, i.e.,output shaft 16 ofdrive unit 12 is rotating at the same angular velocity aspinion 54 is being rotated byring gear 48r viaspur gear 58. This represents an opportune time to shift from the first forward propulsion range into the second forward propulsion range by engaging clutch CII and releasing brake BI(R). At 80 percent of maximum available speed in the second forward propulsion range, third range clutch CIII becomes synchronous in thatcarrier 34 is revolving at the same angular velocity assleeve shaft 30. At this time, shifting from the second forward propulsion range into the third propulsion range can be smoothly effected by engaging the third range clutch CIII as clutch CII is disengaged. In this connection, it should be pointed out that the first second and third range forward propulsion limits represented in FIGURE 3 byarrows drive units - From the foregoing description, it is seen that there is provided an illustrative multi-range, infinitely variable, integral steering transmission for track-laying vehicles, which is compact in size and inexpensive to manufacture, requires a minimal number of component parts, is efficient in operation and affords positive and uniform operator control in all of its multiple speed ranges.
- Since certain changes may be made in the disclosed embodiment without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings be interpreted as illustrated and not in a limiting sense.
Claims (19)
1) a first sun gear,
2) a first ring gear,
3) a first planetary carrier, and
4) a first pinion gear set mounted on said first planetary carrier;
1) a second sun gear,
2) a second ring gear,
3) a second planetary carrier, and
4) a second pinion gear set mounted on said second planetary carrier;
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US128308 | 1987-12-03 | ||
US07/128,308 US4817460A (en) | 1987-12-03 | 1987-12-03 | Infinitely variable steering transmission |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0319323A2 true EP0319323A2 (en) | 1989-06-07 |
EP0319323A3 EP0319323A3 (en) | 1990-09-05 |
Family
ID=22434698
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19880311457 Withdrawn EP0319323A3 (en) | 1987-12-03 | 1988-12-02 | Infinitely variable steering transmission |
Country Status (6)
Country | Link |
---|---|
US (1) | US4817460A (en) |
EP (1) | EP0319323A3 (en) |
JP (1) | JPH01208267A (en) |
KR (1) | KR890009709A (en) |
AU (1) | AU604445B2 (en) |
IL (1) | IL88401A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19631014A1 (en) * | 1996-08-01 | 1998-02-05 | Zahnradfabrik Friedrichshafen | Hydrostatic-mechanical steering gear for tracked vehicles |
DE19631012A1 (en) * | 1996-08-01 | 1998-02-05 | Zahnradfabrik Friedrichshafen | Steering method for tracked vehicles |
DE10344711A1 (en) * | 2003-09-26 | 2005-04-14 | Zf Friedrichshafen Ag | Electrical drive system for a vehicle with sliding steering, has two mechanical gear trains linking first and second drive transmission elements on the left and right sides of the vehicle |
DE102005010516A1 (en) * | 2005-03-08 | 2006-09-21 | Zf Friedrichshafen Ag | Electrical drive for e.g. track vehicle, has prime movers propelling connecting shafts, where speed transformation ratio of one shaft is opposite to ratio of other shaft, where ratios are compensated during rotation of prime movers |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5168946A (en) * | 1991-09-09 | 1992-12-08 | General Electric Company | Track-laying vehicle electric drive system |
US5509491A (en) * | 1994-04-18 | 1996-04-23 | General Motors Corporation | Dual-motor electric drive system for vehicles |
KR100418730B1 (en) * | 1995-09-11 | 2004-05-20 | 혼다 기켄 고교 가부시키가이샤 | Connecting device between left and right wheel of vehicle |
US5730678A (en) * | 1996-02-28 | 1998-03-24 | Gen Dynamics Defense Syst Inc | Multi-range, hydromechanical transmission for motor vehicles |
JP3593575B2 (en) * | 2001-02-08 | 2004-11-24 | 川崎重工業株式会社 | Single-shaft gas turbine system |
US7216579B2 (en) * | 2001-10-17 | 2007-05-15 | Lonmore, L.C. | Variable flow control devices, related applications, and related methods |
US6783474B2 (en) | 2001-12-28 | 2004-08-31 | Visteon Global Technologies, Inc. | Torque controller for controlling torque to two or more shafts |
US7115066B1 (en) * | 2002-02-11 | 2006-10-03 | Lee Paul Z | Continuously variable ratio transmission |
US7108096B1 (en) | 2002-02-25 | 2006-09-19 | Lonmore, Lc | Vehicle control system with slow-in-turn capabilities and related method |
JP7108707B2 (en) * | 2018-11-19 | 2022-07-28 | 川崎重工業株式会社 | Power generation controller for aircraft |
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US3815698A (en) * | 1972-04-20 | 1974-06-11 | Gen Electric | Hydromechanical steering transmission |
EP0102049A2 (en) * | 1982-08-26 | 1984-03-07 | General Electric Company | Simplified hydromechanical steering transmission |
EP0158411A1 (en) * | 1984-02-07 | 1985-10-16 | Torotrak (Development) Limited | Driveline for a track-laying vehicle |
WO1987006316A1 (en) * | 1986-04-10 | 1987-10-22 | Michael Meyerle | Continuous speed-change branched gear, in particular for motor vehicles |
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US3590658A (en) * | 1967-09-28 | 1971-07-06 | Robert M Tuck | Power train |
US3545303A (en) * | 1968-09-27 | 1970-12-08 | Avco Corp | Steering apparatus for transmissions coupled to a free power turbine |
US3575066A (en) * | 1969-09-23 | 1971-04-13 | Gen Motors Corp | Transmission |
US3583256A (en) * | 1969-11-19 | 1971-06-08 | Gen Motors Corp | Transmission |
US4345488A (en) * | 1980-04-21 | 1982-08-24 | General Electric Company | Hydromechanical steering transmission |
JPS58141934A (en) * | 1982-02-17 | 1983-08-23 | Komatsu Ltd | Control of engine speed of hydraulic mechanical type speed change gear and steering unit |
EP0137264B1 (en) * | 1983-08-25 | 1988-11-09 | Torotrak (Development) Limited | Driveline for a track-laying vehicle |
JPS60227045A (en) * | 1984-04-25 | 1985-11-12 | Mitsubishi Heavy Ind Ltd | Speed change steering device |
US4682515A (en) * | 1984-10-11 | 1987-07-28 | General Electric Company | Gear train for four range hydromechanical steering transmission |
-
1987
- 1987-12-03 US US07/128,308 patent/US4817460A/en not_active Expired - Fee Related
-
1988
- 1988-11-11 AU AU25094/88A patent/AU604445B2/en not_active Ceased
- 1988-11-17 IL IL88401A patent/IL88401A/en unknown
- 1988-12-02 KR KR1019880016052A patent/KR890009709A/en not_active Application Discontinuation
- 1988-12-02 EP EP19880311457 patent/EP0319323A3/en not_active Withdrawn
- 1988-12-02 JP JP63304262A patent/JPH01208267A/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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US3815698A (en) * | 1972-04-20 | 1974-06-11 | Gen Electric | Hydromechanical steering transmission |
EP0102049A2 (en) * | 1982-08-26 | 1984-03-07 | General Electric Company | Simplified hydromechanical steering transmission |
EP0158411A1 (en) * | 1984-02-07 | 1985-10-16 | Torotrak (Development) Limited | Driveline for a track-laying vehicle |
WO1987006316A1 (en) * | 1986-04-10 | 1987-10-22 | Michael Meyerle | Continuous speed-change branched gear, in particular for motor vehicles |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19631014A1 (en) * | 1996-08-01 | 1998-02-05 | Zahnradfabrik Friedrichshafen | Hydrostatic-mechanical steering gear for tracked vehicles |
DE19631012A1 (en) * | 1996-08-01 | 1998-02-05 | Zahnradfabrik Friedrichshafen | Steering method for tracked vehicles |
DE19631014C2 (en) * | 1996-08-01 | 2003-05-28 | Zahnradfabrik Friedrichshafen | Hydrostatic-mechanical steering gear |
DE19631012C2 (en) * | 1996-08-01 | 2003-12-11 | Zahnradfabrik Friedrichshafen | Device for steering a tracked vehicle and method for operating this device |
DE10344711A1 (en) * | 2003-09-26 | 2005-04-14 | Zf Friedrichshafen Ag | Electrical drive system for a vehicle with sliding steering, has two mechanical gear trains linking first and second drive transmission elements on the left and right sides of the vehicle |
US7441618B2 (en) | 2003-09-26 | 2008-10-28 | Zf Friedrichshafen Ag | Electrical drive system for a vehicle with skid steering |
DE102005010516A1 (en) * | 2005-03-08 | 2006-09-21 | Zf Friedrichshafen Ag | Electrical drive for e.g. track vehicle, has prime movers propelling connecting shafts, where speed transformation ratio of one shaft is opposite to ratio of other shaft, where ratios are compensated during rotation of prime movers |
Also Published As
Publication number | Publication date |
---|---|
IL88401A (en) | 1991-04-15 |
JPH01208267A (en) | 1989-08-22 |
AU2509488A (en) | 1989-06-08 |
KR890009709A (en) | 1989-08-03 |
IL88401A0 (en) | 1989-06-30 |
AU604445B2 (en) | 1990-12-13 |
EP0319323A3 (en) | 1990-09-05 |
US4817460A (en) | 1989-04-04 |
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